<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script>
    // let i
    // for(i = 1; i <=3; i++) {
    //   setTimeout(function () {
    //     console.log(i)
    //   }, 0)
    // }
    // //4  4  4

    let a = 100
    function test () {
      alert(a)
      a = 10
      alert(a)
    }
    test()
    alert(a)
    //100   10   10
</script>
</html>
